Polyoxyethylenated bisphenol-A for breaking water-in-oil emulsions

Polyethylene glycol (PEG) of different molecular weights, namely, 600, 1000 and 4000 g/mol was reacted with bisphenol A to form compounds having different hydrophile–lipophile balances and hence different surface activities. The interfacial tension at the aqueous/benzene interface was determined. It was found that the concentrations of demulsifiers required to cause a minimum interfacial tension are always less than those inducing a maximum demulsification efficiency. The demulsification efficiency of the prepared surfactants in breaking synthetic water in benzene emulsions stabilized by petroleum asphaltenes was evaluated. The data revealed that the demulsification efficiency increases with increasing demulsifier concentration, contact time and hydrophilicity.     

Propylene oxide-ethylene oxide block copolymers as demulsifiers for water-in-oil emulsions,I. Effect of molecular weight and hydrophilic-lipophylic balance on the demulsification efficiency

Summary A series of propylene oxide (PO)-ethylene oxide (EO) block copolymers with differentEO/PO ratios and molecular weights have been prepared and tested for their demulsification potency in breaking synthetic water-in-benzene emulsions stabilized by asphaltenes. Their partition coefficients between benzene and water were determined by means of UV absorption. NMR spectroscopic analysis was used for determining the actualPO/EO ratios of these block copolymers. The effects of hydrophilic-lipophilic balance (HLB) and molecular weight of the prepared surfactants on their demulsification efficiency were investigated. It was found that the demulsification efficiency is directly proportional to both HLB and molecular weight.

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Propylenoxid-Ethylenoxid-Blockcopolymere als Emulsionsbrecher für Wasser-in-Öl-Emulsionen, 1. Mitt. Effekt des Molekulargewichts und des Hydrophilie-Lipophilie-Gleichgewichts auf die Effizienz der Emulsionsbrechung

Zusammenfassung Eine Reihe von Propylenoxid (PO)-Ethylenoxid (EO) Blockcopolymeren mit verschiedenenEO/PO-Verhältnissen und Molekulargewichten wurden hergestellt und auf ihre Effizienz bezüglich des Brechens von durch Asphalt stabilisierten synthetischen Wasser/Benzol-Emulsionen untersucht. Ihre Verteilungskoeffizienten zwischen Benzol und Wasser wurden mittels UV-Spektroskopie ermittelt. DasPO/EO-Verhältnis wurde NMR-spektroskopisch bestimmt. Die Effekte von Hydrophilie-Lipophilie-Gleichgewicht (HLB) und Molekulargewicht auf die Effizienz der Wirkung wurden untersucht. Das Emulsionsbrechungsvermögen ist direkt proportional zu HLB und indirekt proportional zum Molekulargewicht.

     

Propylene oxide-ethylene oxide block copolymers as demulsifiers for water-in-oil emulsions,II. Effects of temperature,salinity,pH-value,and solvents on the demulsification efficiency

Summary The effects of temperature, NaCl concentration (salinity),pH value, and solvents on the demulsification efficiency of propylene oxide (PO)-ethylene oxide (EO) block copolymers in the breaking of synthetic water-in-benzene emulsions stabilized by petroleum asphaltenes have been thoroughly investigated. The demulsification efficiency of the studied polymeric surfactants was found to increase with increasing temperature and decreasing salinity of the aqueous phase. A neutralpH value of the aqueous phase of the emulsion was found to be optimat for efficient demulsification. Water and water compatible solvents were found to be the best solvents for the prepared demulsifiers with respect to demulsification properties.

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Propylenoxid-Ethylenoxid-Blockcopolymere als Emulsionsbrecher für Wasser-in-Öl-Emulsionen, 2. Mitt.: Einflüsse von Temperatur, Salzgehalt,ph-Wert und Lösungsmitteln auf die Demulsifikationsfähigkeit

Zusammenfassung Die Einflüsse von Temperatur, NaCl-Konzentration,pH-Wert und Lösungsmitteln auf die Fähigkeit von Propylenoxid-Ethylenoxid-Blockcopolymeren (PO-EO), durch Asphalte stabilisierte Wasser-in-Benzol-Emulsionen zu brechen, wurden eingehend studiert. Die Wirksamkeit der untersuchten polymeren oberflächenaktiven Substanzen steigt mit steigender Temperatur und sinkendem Salzgehalt der wäßrigen Phase. Am besten verläuft die Demulsifikation bei neutralempH-Wert. Wasser und vergleichbare Lösungsmittel eignen sich am besten zur Erzielung einer hohen Wirksamkeit der verwendeten Emulsionsbrecher.

     

Demulsification Efficiency of Some New Demulsifiers Based on 1,3,5-Triethanolhexahydro-1,3,5-triazine

This study mainly concentrates on the synthesis of three novel demulsifiers and the investigation of their demulsification efficiency. The demulsifiers were derived from 1,3,5-triethanolhexahydro-1,3,5-triazine, which was prepared by the reaction of monoethanol amine with formaldehyde. The 1,3,5-triethanolhexahydro-1,3,5-triazine was ethoxylated by introducing 20 units of ethylene oxide and then esterified at different molar ratios with oleic acid (1, 2, and 3) to give three demulsifiers, namely, E₂₀TO, E₂₀TO₂, and E₂₀TO₃. The chemical structures of the prepared demulsifiers were confirmed by ¹H NMR and FTIR spectrum. The demulsification efficiency of these demulsifiers was tested on the natural water-in-oil (w/o) emulsions (50% water content). From the obtained results, it has been found that the investigated demulsifiers have a great potential to break the w/o emulsions. The trioleat ester (E₂₀TO₃) exhibited the maximum demulsification efficiency (96%) after 120 minutes at 55°C.     

Time-dependent nucleation of methane hydrate in a water-in-oil emulsion: effect of water redistribution

Nucleation is a key step in preventing gas hydrate formation during oil and gas production. Oil can sharply affect the hydrate nucleation with changing the activity of nucleation centers (mainly at the water–oil interface) over time. The spontaneous emulsification of water-in-oil emulsions in the course of aging can lead to a decrease in the size of water drops and, consequently, facilitate the hydrate nucleation and alter hydrate mitigation during the shut-in period     

Investigation of the Demulsification Efficiency of Some Ethoxylated Polyalkylphenol Formaldehydes Based on Locally Obtained Materials to Resolve Water-in-Oil Emulsions

Fourteen ethoxylated polyalkylphenol formaldehyde surfactants were prepared from locally sourced raw materials. These surfactants were used as demulsifiers to resolve asphltenic crude oil emulsions. Different factors affecting demulsification efficiency such as water:oil ratios, surfactant concentration, surfactant molecular weight, ethylene oxide content, alkyl chain length, and asphaltene content were investigated. From the data obtained it was found that the demulsification efficiency increases by increasing the concentration, alkyl chain length and water content in the emulsion. Also it was found that the increase of asphaltene content in the crude oil impeded the demulsification efficiency. The effect of molecular weight was studied and it was found that the demulsification efficiency was controlled by an optimum range of molecular weight between 3640 to 3810 for the family of demulsifiers studied. Regarding the effect of ethylene oxide content in the demulsifier structure, it was found that the maximum demulsification efficiency was obtaind at 40 units ethylene oxide. The maximum demulsification efficiency was obtained by TND5 (m.wt. = 3800, eo = 40 units). With this demulsifier 100% water separation was exhibited after 35 minutes at 150 ppm demulsifier concentration and 50% w/o emulsion. The surface, interfacial tension, and hydrophilic lipophilic balance (HLB) of the invistigated demulsifers were studied. The obtained results justified that they are strongly related to the demulsification effeciency.     

Nonmonotonic pattern of the critical percolation temperature due to variations of additive chain length in water-in-oil microemulsions

The nonmonotonic variation of the critical percolation temperature (T _c) of ternary nonionic (C₁₄E₅) water-in-oil microemulsions was studied as a function of the alkyl chain length of an ionic additive (n-alkyl sulfonate sodium salt). A thermodynamic approach shows the relationship between T _c and additive chain length, which is supplemented by a consideration of a possible molecular mechanism of the observed phenomenon. Received: 20 October 2000 Accepted: 7 November 2000     

Study on the flow of highly concentrated emulsions

An investigation was performed into the flow of highly concentrated water-in-oil emulsions. The viscosity of the low shear rate region in the downward curve was much higher than the viscosity of the upward curve due to the refining effect of the intensive shear. However, this refining effect lasted for just a short time. After that, the structure of highly concentrated emulsion (HCE) can return to its original state. The flow of HCE depends on the shear rate and droplet size of the dispersed phase. The viscosity curve of HCE, which is measured in the initial upward shearing sweep, had two platforms, whereas the region of shear rate was 10^?4?s^?1?～?10³?s^?1. The water-in-oil structure was destroyed by intensive shear and much solid ammonium nitrate (AN) was observed in the image of HCE. The small droplets can enhance the capacity of HCE to prevent the breakage of structure under shearing. The microstructure of HCE was closer to its original situation when the droplet size was small.     

Application of Pd-catalysed amines arylation for the synthesis of benzopolyazamacrocycles

Amination of 1,2- or 1,3-dihalobenzenes by linear polyamines in the presence of Pd(dba)₂/BINAP catalytic system can serve as a convenient one-pot procedure for the synthesis of benzopolyazamacrocycles.     

Direct Leuckart-type reductive amination of aldehydes and ketones: a facile one-pot protocol for the preparation of secondary and tertiary amines

A high-yielding and facile one-pot Leuckart-type reaction for rapid access to a number of 2° and 3° amines is described.     

Influence of composition on the encapsulation properties of P/O/W multiple emulsions for Vitamin C

Abstract

The aim of this work was to study the encapsulation properties of polyols-in-oil-in-water (P/O/W) multiple emulsions for Vitamin C (Vc). The influence of formulation factors, including the concentration of lipophilic emulsifier, hydrophilic emulsifier, salt and glycerol had been investigated. The results indicated that the encapsulation stability could be improved by increasing the lipophilic emulsifier concentration which could strengthen the interfacial film. In contrast, the excess of hydrophilic emulsifier destabilized the emulsion. The presence of glycerol in the outer aqueous phase accelerated the phase transfer, thus reduced the encapsulation rate. The addition of salt in inner polyols phase had little effect on encapsulation rate while markedly affected the morphology and stability of this system. P/O/W multiple emulsions showed better encapsulation stability than the W/O/W multiple emulsions as the former’s encapsulation rate could remain more than 75% after 2?weeks while the latter only remained less than 60%. Meanwhile, the P/O/W emulsions exhibited higher storage modulus (G’), bigger loss modulus (G’’) and broaden linear viscoelastic regions than W/O/W emulsions.     

Effect of liquid oils on the properties of multiple emulsions containing liquid crystals

Recently, many cosmetic researchers have been focused on multiple emulsions due to better performance. Limited application of multiple emulsions has been attributed to their instability, which can be resolved by the presence of liquid crystals. Multiple emulsions containing liquid crystals are affected by various formulation parameters, such as liquid oils. In this paper, the influence of liquid oils on the formation mechanism was studied. Besides, stability, small-angle x-ray scattering (SAXS) spectra analysis, and rheological analysis of the emulsions were investigated as well. The results showed that when the gap of the polarity between inner oils and external liquid oils is greater, the multiple structures were more easily formed. Multiple emulsions containing liquid crystals were superior in stability to multiple emulsions prepared in the same way with liquid oils that did not form liquid crystals. SAXS indicated that the liquid crystal orientation was lamellar. Rheological analysis indicated that the different structure emulsions showed shear-thinning behavior. The presence of liquid crystal decreased the viscosity and resulted in pseudoplastic enhancement. Both the storage modulus (G′) and the loss modulus (G″) of multiple emulsions were slightly higher than those of O/W-type emulsions, implying the existence of multiple structures.     

Peculiarities of the effect of the electronic nature of substituents on the basic properties of aliphatic amines

Changes in the hybrid state of atomic orbitals of nitrogen and p-character of LEP, which occur under the effect of saturated hydrocarbon radicals and polar substituents in aliphatic amines, differ substantially. Therefore, the effect of the both substituents on the basicity constants of amines cannot be described by the single formal type of interaction. The anomalous changes in the basicity in the series of primary, secondary, and tertiary alkylamines, which are discussed in the literature, and the correlations pK _BH+ = f(*) and G _B = f(*) are, in fact, imaginary, because the alkyl radicals at the N atom do not manifest the electron-donor properties.     

A new versatile linker for the solid-phase synthesis of secondary amines

A novel linker for the solid-phase synthesis of secondary amines based on an intramolecular cyclization was developed. The linker allows for a stepwise built-up of the secondary amines on the support. The feasibility was demonstrated in the parallel synthesis of a small set of different secondary amines.     

Validation of a method for the analysis of biogenic amines: Histamine instability during wine sample storage

This paper reports on the development of an optimized method for the simultaneous analysis of eight biogenic amines (histamine, methylamine, ethylamine, tyramine, putrescine, cadaverine, phenethylamine, and isoamylamine). The analytical method thus proposed has the following advantages: the easy derivatization of wine, the quantification of biogenic amines and a complete degradation of excess derivatization reagent during sample preparation in order to preserve the column. It consists in reversed phase separation by HPLC and UV–vis detection of the aminoenones formed by the reaction of amino compounds with the derivatization reagent diethyl ethoxymethylenemalonate (DEEMM). The usefulness of this technique was confirmed by an alternative oenological analytical method for the validation, quality control and uncertainty assessment (OIV Oeno 10/2005). The method was validated and proposed as a reference method to the International Organization of Vine and Wine (OIV). As a specific application of the proposed method, the biogenic amine content of Rhône valley wines was investigated.     

Star-shaped tripodal chemosensors for the detection of aliphatic amines

In this work, three new tripodal triphenylamine dyes are presented that are capable of reversibly binding amines and diamines to form hemiaminals through a covalent bond. The dyes were synthesized by the Heck reaction and possess stilbene units with one, two, or three trifluoroacetyl groups as receptor moieties. Their interaction with amines and diamines led to changes in their absorption and emission properties, which were detected by UV/Vis and fluorescence spectroscopy. The influence of the number of trifluoroacetyl receptor moieties on the selectivity and sensitivity of the dyes was studied. Enhanced sensitivity and selectivity for diaminoalkanes was found for the dye we have labeled Tripod-1, with three chemically reactive trifluoroacetyl groups, related to only one or two trifluoroacetyl groups in the dye molecule.     

Effects of compositions on the stability of polyols-in-oil-in-water (P/O/W) multiple emulsions

Polyols-in-oil-in-water (P/O/W) multiple emulsions were successfully prepared by using polyols as inner aqueous phase to avoid instabilities caused by water. The influence of polyols, oils and emulsifiers on the morphology and stability of P/O/W multiple emulsions were studied and the stability mechanisms of this new kind of multiple emulsions were also explored. Glycerol that has the worst solubility in oil phase contributed to the formation of stable inner droplets which agree with the Ostwald Ripening theory. Mineral oil worked well with the system proving that oils possessing similar solubility parameters with the hydrophobic group of emulsifiers benefited for system stability. Several typical surfactants had been investigated in this article, and it turned out that emulsifiers Cetyl PEG/PPG-10/1 Dimethicone and the block copolymer Poloxamer 407 were suitable for the P/O/W system. The stability of the system affected by different compositions was evaluated based on microscopic observation and rheological measurements. The novel multiple emulsions will provide enlightening recommendations for future investigations and applications in cosmetic, food and pharmaceuticals, including drug delivery and the encapsulation of hydrophilic actives and actives that are soluble in polyols.     

A reaction of nitroxides with ethyl mercaptane: A mild method for the conversion of nitroxides into their corresponding amines

Summary The mild reduction of the nitroxides1 a–j to the corresponding sterically hindered amines2 a–j by means of ethyl mercaptane is reported. The reaction mixtures of1 a, b, g were analyzed by glc/ms.

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Die Reaktion von Nitroxiden mit Ethylmercaptan: Eine milde Methode für die Umsetzung von Nitroxiden zu den entsprechenden Aminen

Zusammenfassung Es wird über die milde Reduktion der Nitroxide1 a–j zu den entsprechenden sterisch gehinderten Aminen2 a–j mittels Ethylmerkaptan berichtet. Die Reaktionsmischungen von1 a, b, g wurden mittels GLC/MS analysiert.